Lactols from Physalis grisea.

From the extracts of stems and leaves as well as of calyxes of Physalis grisea were isolated four withalactols, the new griselactols A (3) and B (6) and the known physapubescin (1) and peruvianolide E (2). Other four known compounds were also isolated, kaempferol 3-O-ß-sophoroside (5) and three sterols. The structures of compounds were elucidated by extensive spectroscopic data analyses, chemical and physical-chemical methods, including electronic circular dichroism (ECD), and by comparison with data described in the literature. The antihyperglycemic activity of the extracts and of the three more abundant metabolites (1, 3, and 5) was evaluated in the α-glucosidase inhibition assay.

Recognition of antioxidants and photosensitizers in Dyssodia pinnata by EPR spectroscopy.

INTRODUCTION: Previous studies report the isolation mainly of terthiophene derivatives and flavonoids from Dyssodia species. Terthiophenes are known as photosensitizers by their capacity to generate singlet oxygen (1 O2 ), and flavonoid antioxidant activity is recognized. These opposite properties could represent interesting options in photodynamic therapy. OBJECTIVE: To determine the antioxidant and photosensitizer activities of extracts and isolates of Dyssodia pinnata by electron paramagnetic resonance (EPR). METHODOLOGY: Extracts and isolates were evaluated as antioxidants by the interactions with copper ion (Cu2+ ) observed in EPR, and by the 2,2-diphenyl-1-picrylhydrazyl radical (DPPH) and the thiobarbituric reactive substances (TBARS) methods. Their abilities as 1 O2 producers were also estimated by EPR. RESULTS: Terthiophenes were obtained from hexane (DPH) and acetone (DPA) extracts, and flavonoids from DPA and methanol (DPM) extracts. The interaction with Cu2+ of extracts and isolated compounds of Dyssodia pinnata showed two effects in EPR: reduction and chelation; flavonoids exhibited both effects, while terthiophenes showed only reduction. DPA, DPM, and flavonoids were active in DPPH and TBARS assays. Quercetagetin-7-O-ß-glucoside showed the highest antioxidant and chelating activities, 3-glycosidated flavonoids were less active. Upon irradiation extracts and terthiophenes induced 1 O2 formation. CONCLUSION: Flavonoid reducing activity on Cu2+ and free radical scavenging capacity were related to the number of hydroxy groups and to the conjugation between the B and C rings. All tested flavonols showed a major complex with Cu2+ , with the most probable site of chelation between the 5-hydroxy and 4-oxo groups. Extracts and terthiophene derivatives showed photosensitizer activity. Thus, EPR is useful to evaluate free radical scavenging and pro-oxidant properties.

Chemical constituents of Roldana lineolata.

The new eremophilanolide 1, the known eremophilane derivatives 2 and 3, already described as part of mixtures, the known compounds hyperin, 2''-acetylhyperin and two calenduladiol esters were isolated from Roldana lineolata. Their structures were determined by spectroscopic methods. Compounds 1 and 2 as well as their acetylated and oxidized derivatives were tested against several fungi strains. Eremophilanolide 1 showed a mild activity against Trichophyton mentagrophytes.

Cacalol derivatives from Roldana angulifolia.

Four new modified eremophilanes, angulifolide (1) and angulifolins A-C (2-4), and two new triacetylglucosides (7 and 8) were isolated from Roldana angulifolia, together with several known compounds. The structures of the new compounds were elucidated by spectroscopic analysis and chemical reactions. The absolute configuration of compounds 2 and 3 was established by Mosher ester methodology. Cytotoxicity against selected human cancer cell lines was determined for the more abundant isolated metabolites.

Eremophilanes from Senecio mairetianus and some reaction products.

Eight new eremophilanolides (1, 2, 4-7, 9, and 10), a new eremophilane (13), and several known compounds were isolated from the roots and aerial parts of Senecio mairetianus. The chemical structures were proposed taking into consideration spectroscopic analyses and chemical transformations. X-ray diffraction analysis of 2, 4, and 9 confirmed their structures. The stereochemistry of 1,10-epoxy-8alpha-methoxyermophilanolide (3) was determined. Compounds 4-7, 9, and 10 are possible artifacts obtained by preparation of the alkaloidal extract.

Labdanes and withanolides from Physalis coztomatl.

Aerial parts of Physalis coztomatl afforded a new labdane diterpene, physacoztomatin (1), and five new withanolides, physacoztolides A-E (5-9). Six known compounds were also isolated. The structures of the new compounds were established after analyses of their spectroscopic data and by means of chemical transformations. X-ray diffraction analyses of 15-dehydrophysacoztomatin (2) and 5 confirmed the structures of 1 and 5. Labd-13(E)-ene-8alpha,15-diol (4) and physacoztomatin (1) represent the first labdane diterpenes isolated from the genus Physalis.

Androstane and withanolides from Physalis cinerascens.

Two new withanolides, cinerolide and 24,25-dihydrowithanolide S, together with the new androstane, cinedione, and the known withanolides, visconolide, physalactone, withanolide S and 4beta-hydroxywithanolide E were isolated from the EtOAc extract of leaves, flowers and stems of Physalis cinerascens. The structures of these compounds were established by spectroscopic methods and that of cinerolide was confirmed by X-ray diffraction analysis.

Anti-inflammatory constituents of Mortonia greggii Gray.

A new phytochemical study of Mortonia greggii (Celastraceae) afforded four friedelan derivatives (1-4), three lupanes (5-7), retusine (8), two esterified polyhydroxyagarofurans (9-10), mortonin C (11) and photomortonin C (12). The anti-inflammatory activity on carrageenan and 12-O-tetradecanoylphorbol-13-acetate induced models of inflammation, as well as the ability to inhibit the nitric oxide (NO) produced by lipopolysaccharide-stimulated mouse peritoneal macrophages were evaluated for the main metabolites. Our results showed that the friedelan dehydrocanophyllic acid methyl ester (1) exhibits an anti-inflammatory effect which could be related to an inhibition of prostaglandin and NO production. The activity of lupeol (5), 29-hydroxylupeol (6) and 29-hydroxylupenone (7) might be involved with the prostanoid synthesis. The presence of the hydroxy groups in 6 appears to be important for activity. The edema inhibition capacity of retusine (8) could be related to a reduction of the prostaglandin production. The agarofuran derivative 10 is an NO inhibitor whose activity is probably not involved in the synthesis of prostaglandins.

Insect growth inhibition by tocotrienols and hydroquinones from Roldana barba-johannis.

The methanol extract from the aerial parts of Roldana barba-johannis (Asteraceae) afforded sargachromenol, sargahydroquinoic acid, and sargaquinoic acid. These natural products and their corresponding acetylated and methylated derivatives showed insecticidal and insect growth regulatory activities against the Fall Armyworm [Spodoptera frugiperda J.E. Smith, (Lepidoptera: Noctuidae)], an important insect pest of corn. The most active compounds were sargachromenol and its acetylated derivative; sargahydroquinoic acid and its acetylated derivative; and a mixture of sargachromenol, sargahydroquinoic acid, and sargaquinoic acid (6:3:1) and the acetylated form of this mixture. All these compounds and mixtures had significant inhibitory effects between 5.0 and 20.0 ppm in diets. Most compounds were insecticidal to larvae, with lethal doses between 20 and 35 ppm. In addition, these substances also demonstrated scavenging properties toward 2,2-diphenyl-1-picrylhydrazyl radical in TLC autographic and spectrophotometric assays. These compounds appear to have selective effects on the pre-emergence metabolism of the insect. The results from these compounds were fully comparable in activity to those known natural insect growth inhibitors such as gedunin and methanol extracts of Cedrela salvadorensis and Yucca periculosa. These substances may be useful as natural insecticidal agents.

18-Acetoxywithanolides from Physalis chenopodifolia1.

Five new withasteroids, physachenolides A - E were isolated from the acetone and methanol extracts of leaves, flowers and stems of Physalis chenopodifolia Lam. The structural assignments of these compounds were based on spectral evidence. The absolute configuration of physachenolide A was established by X-ray analysis.

New oplopane and eremophilane derivatives from Robinsonecio gerberifolius.

A phytochemical study of Robinsonecio gerberifolius afforded six new sesquiterpenoids, two oplopane (1and 2) and four eremophilane derivatives (3-6). The structures of these compounds were elucidated on spectroscopic grounds, and the absolute configurations of compounds 3 and 4 were established from CD analysis. The known 3beta-angeloyloxy-1,10-epoxyfuranoeremophilane (7) was also isolated, and its stereochemistry was revised. The cytotoxic activities of compounds 1-7 were determined against five human cancer cell lines.

Evaluation of the anti-inflammatory and antioxidant activities of the plastoquinone derivatives isolated from Roldana barba-johannis.

A phytochemical study of Roldana barba-johannis afforded two triterpenic esters, an eremophilanolide and three compounds structurally related to the antioxidants vitamin E and plastoquinone. Evaluation of the anti-inflammatory and antioxidant activities of sargahydroquinoic acid, sargachromenol, their mixture, and their methyl esters showed that most of them are antioxidant and anti-inflammatory agents.